A SUGGESTED CYCLE OF PLASTID DEVELOPMENTAL INTERRELATIONSHIPS

Abstract

It is suggested that developmental changes in plastid structure follow a cyclic pathway which may involve the dedifferentiation of mature chloroplasts to proplastids and the subsequent redifferentiation of proplastids to mature chloroplasts. The proposal of a cyclic plastid relationship revives the earlier concept of Schimper. This has generally been discarded in favour of a unidirectional concept which discounts dedifferentiation as a normal process. Justification of the cyclic concept depends largely on the verification that plastid dedifferentiation and re differentiation do indeed take place. Evidence for this comes not only from the literature, but also from personal observations. Copyright © 1978, Wiley Blackwell. All rights reserved